The phosphorus concentration in the water was low in the mixed planting pattern,
compared with either of the two monocultures ( Figures.1-3). For TP concentration in
water, the average value was 0.12 mg l-1 in the mixture and 0.17 mg l-1 and 0.16 mg l-1 in the two monocultures of V. natans and H. verticillata, respectively (Figure 1) .
No significant differences were observed for TSP (Figure 2) or SRP (Figure 3) concentrations in the water between mixed and monocultures (p>0.05). The SRP concentrations were particularly low (Figure 3) ; the SRP: TP ratio was only about 3%.